Self-propelled wheel chair



5 Sheets-Sheet l Filed July ll, 1960 INVENTOR. #4i/@V62 JENA/W65 u?! @MwNOV 20, 1962 H. c. JENNlNGs 3,064,744

SELF-PROPELLED WHEEL CHAIR Nov. ZO, 1962 H. c. JENNINGS 3,064,744

SELF-PROPELLED WHEEL CHAIR Filed July ll, 1960 3 Sheets-Sheet 3 IillllIIIIIIIIIII J JNVENTOR. 5 7 #469V c. ./EA/A//A/@s 5 56 BY www@ nitedStates @t `lennings, Inc., Los Angeles, Calif., a corporation ofCalifornia Filed July llll, 196i), Ser. No. 41,988 2 Claims. (Cl.Mil-6.5)

This invention relates to improvements in self-propelled invalid wheelchairs.

A primary object of the invention is to provide a wheel chair which hastwo separate electric motor drives, one for each drive wheel of thechair and arranged in a novel manner adjacent each side frame of thechair so that when the storage batteries and supporting frame thereforare removed from the chair the drives for the drive wheels will be solocated -as not to interfere with the collapse of the chair which willenable it to be readily transported or stored in a relatively smallspace.

Another object of the invention is to provide an invalid wheel chairhaving two separate, reversible electric motor drives enabling eitherdrive wheel to be driven forwardly or rearwardly independently of eachother. Such a drive is necessary to enable the chair to be drivenforwardly or rearwardly, or by driving one wheel forwardly while theother wheel is driven rearwardly, to effect a turning of the chair. Suchmotor drives frequently will not drive the drive wheels forwardly orrearwardly in perfect synchronism with each other. Consequently, if thechair is being propelled forwardly and one drive Wheel is being drivenslightly faster than the other, the chair will tend to deviate from astraightforward path.

With the foregoing and other objects in view, which will be mademanifest in the following detailed description and specifically pointedout in the appended claims, reference is had to the accompanyingdrawings for 4an illustrative embodiment of the invention, wherein:

FIGURE l is a rear view in elevation of the invalid wheel chair embodingthe present invention;

FG. 2 is a front view in elevation of the same;

FIG. 3 is a side view in elevation of the same;

FIG. 4 is a partial view in vertical section taken substantially uponthe line 4 4 upon FIG. 2 in the direction indicated;

FIG. 5 is a partial view in vertical section taken substantially uponthe line 5 5 upon FIG. 2;

FIG. 6 is a partial view in horizontal section taken substantially uponthe line 6 6 upon FIG. 3; and

FIG. 7 is a partial view taken substantially upon the line 7 7 upon FIG.2.

Referring to the accompanying drawings wherein similar referencecharacters designate similar parts throughout, the improved invalidwheel chair consists essentially of two opposed side frames generallyindicated at 10 and 11. Each side frame has a rear leg 12 extendingupwardly and providing sides 13 for a rbackrest which sides terminatesin handles 14 by which the chair can be manually propelled by a personother than an invalid.

At the bottoms of the rear legs 12 there are bottom members 15, theforward ends of which have extensions welded thereto which are bentupwardly as at 16 and which are connected to front legs 17. The upperends of the front legs are rigidly connected to the rear legs byhorizontal members 1S.

Portions of the bottom members have knuckles 19 rotatably mountedthereon to which the lower ends of X-brace members 2li are rigidlysecured. These X-brace members are pivotally connected to each other bya pivot bolt 21. Their upper ends are rigidly secured to seat rails 22,the forward ends of which have ttings 23 pivotally mounted thereon thatcarry portions 24 that arent C telescope downwardly within the frontlegs 17. The rear ends of the seat rails have pivotally mounted thereonclaws which slide upwardly on the rear legs 13.

A flexible seat 25 connects the seat rails and in a similar manner, aflexible backrest 26 connects the rear legs 13. On the outer sides ofthe side frames there are sockets 27 rigidly secured thereto whichreceive the lower ends of armrest supports 28 supporting armrests 29.

The above-described construction conforms particularly to one design ofwheel chair which can be collapsed by merely pushing the side frames liland 11 towards each other. During such movement of the side framestowards each other the members 20 of the X-brace merely pivot on theirpivot bolt 2l and the seat rails 22 rise with respect to the sideframes, such movement being permitted by the rotatable connectionbetween the ttings 23 and the forward ends of the seat rails and therotatable connections between the claws at the rear ends of the seatrails. When the seat rails rise the portions 24 merely rise partiallyfrom within the front legs 17 and the claws at the rear ends of the seatrails merely slide upwardly on the rear legs 13.

The swinging movements of the lower ends of the X-brace members 2li withrespect to the bottom member l5 is afforded by the rotatable connectionbetween the sleeves 19 with their respective bottom members.

At the rear ends of the side frames lll and 11 there are rigidly securedaxle housings 30 that serve to mount axles for independently rotatabledrive wheels 31 and 32. Similarly, at the lower ends of the front leg 17there are rigidly mounted housings 33 for the spindles of forks 34 ofcaster wheels 35, it being understood that the spindles for the forks 34enable the forks and caster wheels to be turned relatively to the sideframes 10 and 11 in any required direction.

Each drive wheel has rigidly secured thereto such as by brackets 36 adrive rim 37 around which is trained an endless belt 38. Each belt 38 isalso trained around a drive pulley 39 that is rotatably mounted on thehousing for a reversible electric motor 40. The housing for eachelectric motor is pivotally mounted as at 41 so as to be suspended fromthe top member 18 of its respective side frame. Each belt 38 is alsotrained around a tightener pulley `42 that is rotatably mounted as at 43on a link 44 that is pivotally mounted as at 45 on the motor housing 40.A link 46 is pivotally mounted as at 47 to each rear leg 12 of the sideframes and is pivotally connected as at 48 to the rear end of itsrespective link 44. A handle 49 is rigidly mounted on each link 46 andhas a twisted portion engageable with ratchet teeth 50 on a bracket 51that is rigidly secured to each top member 18 of the side frames. Thus,by moving the handle 49 forwardly or rearwardly on disengaging theratchet teeth the links 44 and 46 can be caused to assume positions ofgreater angularity with respect to each other than as shown in FIG. 4,or more nearly approaching positions in alignment with each other. Thecloser that these links are in alignment with each other causes thetightener pulley 42 to tighten the belt 38 to a greater extent.Conversely, if the angular relationship between the links 44 and 46 isgreater than that illustrated the elfect of the tightener pulley on thebelt 38 is to loosen it. The change in position of the links 44 and 46is permissible by the motor housing 40 merely pivoting at 41 on its sideframe. The reversible motors within the motor housings 40 are suppliedwith electric current from one or more storage batteries 52 which aresupported on a storage battery holder 53 that rests on the side frames16 and 11 between the rear legs 13. 'These storage batteries areelectrically connected through a control box 54 that is mounted on oneof the side frames and the control box in turn is electrically connectedto a steering control box 55 mounted on one of the side frames.

The steering control box has a handle 56 that is mounted for universalmovement in the box and is engageable with four contacts therein.Forward tilting of the handle 56 causes both electric motors to beenergized to drive both drive Wheels forwardly. Conversely, rearwardtilting of the handle 56 causes both motors to be reversely driven andto drive both drive wheels reawardly. If the handle 56 is tilted towardthe left the motor driving the right-hand drive wheel is drivenforwardly but the motor driving the left-hand drive wheel is drivenrearwardly thus causing the wheel chair to be turned to the left. Theconverse situation exists when the handle 56 is tilted toward the right.

It frequently is very difficult to have both motors drive theirrespective drive wheels at exactly the same speed particularly when beltdrives are employed Such as those illustrated. If one drive wheel isdriven slightly faster than the other the wheel chair will tend todeviate from a straight path. To overcome this the forks 34 on thecaster wheels are equipped with flanges 57 in which there are apertures58, see FIG. 5, engageable by detents 59 that are urged downwardly bythe compression springs 60. The compression of the compression springscan be adjusted by threaded adjusting bolts 61. These detents arelocated in housings 62 on the forward sides of the spindle housings 33.The apertures 58 are so located on the flanges 57 that when they areengaged by the detents 59 the forks 34 of the caster wheels 35 directthe caster wheels in a straight-forward direction. When the casterwheels are held in this direction they will cause the wheel chair toproceed in a straight-forward direction regardless of the fact thateither drive wheel may be urged to rotate a little faster or a littleslower than the other drive wheel.

When the handle 56 is tilted either to the right or to the left causingthe drive wheels to be reversely driven the effort exerted therebytowards turning the wheel chair is sufficient to cause the caste-rwheels to turn their flanges 57 and cam the detents S9 out of theapertures 58. Once that the detents 59 are cammed out of their aperturesthe caster wheels 35 are then free to turn in any direction required.However, whenever the turn has been completed and the wheel chair isreturned into a straight-forward direction the detents 59 will return totheir positions in the apertures 58 and thus releasably hold the casterwheels in positions that will require the Wheel chair to proceed in astraight-forward direction. It will be observed that in this arrangementthat each deter1t59 will offer a considerable resistance to an initialdeparture of caster wheels I from their straight ahead positions, butthat after the detent is cammed out of the aperture 58, that the detentcan then slide rather freely on the flange 57. Consequently, if there isany effort to return a caster wheel toward its straight ahead positionthis can be rather easily accomplished until the detent 59 snaps intoits aperture 58. It is usually undesirable to have a caster wheel urgedto return to its straight ahead position with greater effort the fartherthat it is turned from the straight ahead position. It is more desirableto have the greatest effort required to make the initial departure froma straight ahead position, and after such departure has been made, tohave further turning of the caster Wheel accomplished quite easily.

A feature of the invention concerns the footrests. On the forward legs17 of the side frames there are vertically aligned upstanding pins 63and 64. The footrests supports which support the footrests 66 have ears67 and 68 mounted thereon which are receivable over the pins 63 and 64,respectively. The tops of the footrests supports 65 are shaped to tagainst the forward sides of the front legs 17. The ears 68 also extendaround the forward sides of the front legs 17 and are equipped withinclined camming surfaces 69, see FIG. 7. Near these camming surfacesthe ears are provided with apertures adapted to partially receive springurged detents 70 that 4 are vertically slidable in housings 71 and whichcan be lifted by handles 72. When a handle 72 is lifted to disengage thedetent 70 from the ear 68, its footrest supports and footrest 66 canthen be swung outwardly about the pins 63 and 64 as centers. When bothfootrests supports are swung outwardly the front of the wheel chair isleft open and unobstructed by the footrests so that the wheel chair canbe driven up close to tables and the like.

Whenever it is desired to return the footrests to their normal positionsforwardly of the wheel chair, it is merely necesssary to swing thefootrests supports 65 inwardly or towards each other. In the course ofthis swinging movement the camming surface 69 on the ear 68 engages thedetent and cams it upwardly until the footrests support has reached itsposition extending forwardly of the front leg. In that position thedetent 70 which is springactuated is automatically snapped into itsaperture in the ear 63 releasably locking the footrest in its normalposition.

One important feature of the invention resides in the nature of thebelts 38, the drive rims 37 and the drive pulleys 39. The drive pulleys39 are in the nature of V pulleys and the drive belts 38 are V beltsdesigned to fit the drive pulleys 39. However, the rims 37 on the drivewheels are in the form of flat pulleys. If the rims 37 are made ofV-shaped form to tit and accommodate the V belt 3S it becomes almostimpossible to push the chair manually even though the belts may be inthe Slack positions. Under these circumstances, the V belts tend to grabin the V of the rim even though they are slack. If the rims 37 are inthe form of fiat pulleys the bottoms of the V belts slide easilyrelatively thereto in the slack position even though they are passingaround a large flat rim.

When the idler 42 is tightened by manipulation of the handle 49 it movesup between the driven rim 37 and the drive pulley 39 tending to producea greater wrap-around of the belt around both the drive pulley 39 andthe rim 37. The greater wrap-around of these pulleys that it is possible to obtain allows less tension to be exerted on the V belt 33.Thus, the idler functions not only as a clutch to tighten the V belt buton being tightened tends to produce greater wrap-around each pulley. Italso serves as a brake when the chair is not in motion because of thegear reduction in the drive between the motor and the drive pulley 39.The links 44, 46, and 49 are in a position to give a toggle effect withgreat mechanical advantage in moving the idler 42 into belt-tighteningposition.

From the above-described construction it will be appreciated that animproved self-propelled invalid wheel chair has been provided havingmany novel advantages. Whenever it is desired to collapse the wheelchair the battery support 53 and the batteries must be disconnected andremoved. However, when the batteries and the battery support are removedthe arrangement of the motors and their motor housings 40 and the beltdrives to the drive wheels is such that the wheel chair can be collapsedin the usual manner. This is due to the fact that the motors and thedrives are located within the planes of the side frames or substantiallyso.

Although one drive wheel may be urged to rotate faster or slower thanits companion drive wheel, nevertheless by means of the detents 59 thecaster wheels can be kept headed in a straight-forward direction untilsuch time as it is desired to make an intentional turn. When this isdesired proper manipulation of the handle 56 will cause the drive wheelsto urge the chair to turn with sufficient effort to cam the detents 59out of their apertures S8 and thus allow the wheel chair to be turned.The drive construction does not prevent the use of footrests which canoptionally be swung outward or returned to their normal positionsextending forwardly of the front legs and releasably locked therein.

Various changes may be made in the details of construction withoutdeparting from the spirit and scope of the invention as defined by theappended claims.

I claim:

1. A self-propelled invalid wheel chair having two opposed side frames,drive wheels and caster wheels rotatably mounted on said side frames, adrive rirn rigid with each drive wheel, an electric motor swingablymounted on each side frame having associated therewith a drive pulleydriven thereby, a pair of links for each side frame, one link of eachpair being pivotally connected to the other link of each pair, one linkof each pair being pivotally connected to the rnotor on its side frameand the other tween the links of each pair, an idler pulley mounted forj rotation on one of the links of each pair, and endless belts trainedover the drive rims, drive pulleys, and idler pulleys.

2. A self-propelled invalid wheel chair having two opposed side frames,drive wheels and caster wheels rotatably mounted on said side frames, adrive rim rigid with each drive Wheel, an electric motor swingablymounted on each side frame having associated therewith a drive pulleydriven thereby, a pair of links for each side frame, one link of eachpair being pivotally connected to the other link of each pair, one linkof each pair being pivotally connected to the motor on its side frameand the other link of each pair being pivotally connected to its sideframe, a handle rigid with one of the links of each pair by which theangular relationship between the links of each pair may be varied, meansfor releasably holding the handle in adjusted position, an idler pulleymounted for rotation on one of the links of each pair, and endless beltstrained over the drive rims, drive pulleys, and idler pulleys.

ieei'ences Cited in the tile of this patent UNITED STATES PATENTS l641,514 Hunt Ian. 16, 190() 2,272,981 Nelson Feb. 10i, 1942 2,456,088Scircle Dec. 14, 1948 2,474,085 Albright I une 21, 1949 2,567,065Ginsterblum Sept. 4, 1951 2,592,449 Miller Apr. 8, 1952 2,798,565Rosenthal et al. July 9, 1957 2,862,569 Strunk Dec. 2, 1958

